Electrodeposition vs Slurry Casting: How Fabrication Affects Electrochemical Reactions of Sb Electrodes in Sodium-Ion Batteries

Abstract

Antimony (Sb) electrodes are an ideal anode material for sodium-ion batteries, which are an attractive energy storage system to support grid-level energy storage. These anodes have high thermal stability, good rate performance, and good electronic conductivity, but there are limitations on the fundamental understanding of phases present as the material is sodiated and desodiated. Therefore, detailed investigations of the impact of the structure-property relationships on the performance of Sb electrodes are crucial for understanding how the degradation mechanisms of these electrodes can be controlled. Although significant work has gone into understanding the sodiation/desodiation mechanism of Sb-based anodes, the fabrication method, electrode composition and experimental parameters vary tremendously and there are discrepancies in the reported sodiation/desodiation reactions. Here we report the use of electrodeposition and slurry casting to fabricate Sb composite films to investigate how different fabrication techniques influence observed sodiation/desodiation reactions. We report that electrode fabrication techniques can dramatically impact the sodiation/desodiation reaction mechanism due to mechanical stability, morphology, and composition of the film. Electrodeposition has been shown to be a viable fabrication technique to process anode materials and to study reaction mechanisms at longer lengths scales without the convolution of binders and additives.

Structural Control of Electrodeposited Sb Anodes through Solution Additives and Their Influence on Electrochemical Performance in Na-Ion Batteries

“…In SPS films, considerable anisotropic broadening is observed, indicating strain in the [104]. Strain in this direction could be caused by the fact that this plane is nearly perpendicular to the (102̅), and rapid growth in the [102̅] could cause strain in the perpendicular direction. ,, …”

“…The base electrodeposition solution of Sb has been described in previous work and consists of 200 mM sodium gluconate (Sigma, ACS reagent), and 30 mM antimony trichloride (SbCl 3 , Sigma-Aldrich, anhydrous >99.0%) in 100 mL of Millipore (>15 MΩ• cm) water. 22 Solution additives were added in a variety of concentrations (1 mM, 10 mM, 30 mM) for (1-hexadecyl)trimethylammonium bromide (CTAB, 98%, Alfa Aesar) and bis(sodium sulfoproply)-disulfide (SPS, 98.9%, CHEM-IMPEX). In addition, a mixed solution containing both CTAB and SPS was made using the base solution and a concentration of 30 mM CTAB and 30 mM SPS.…”

“…The no additive film is the most crystalline, and does exhibit microstrain, consistent with the fact that strain is common in electrodeposited films. 22,67,68 Large crystallites of 1 mM SPS and CTAB films are similar in size at ∼70 nm, though the CTAB film also has a low crystalline Sb component, <2 nm, so overall the 1 mM CTAB film is less crystalline. The SPS films are considerably more crystalline for the remaining concentrations of additives than their CTAB counterparts, and crystallite size does not change substantially until a poorly crystalline Sb phase emerges at 30 mM SPS.…”

“…Strain in this direction could be caused by the fact that this plane is nearly perpendicular to the (102̅ ), and rapid growth in the [102̅ ] could cause strain in the perpendicular direction. 22,67,68 In both additive systems, film crystallinity decreases and strain increases with a higher additive concentration. CTAB appears to have a more drastic effect on film microstructure for a given additive concentration.…”

Spontaneous solid electrolyte interface formation in uncycled sodium half-cell batteries: using X-ray photoelectron spectroscopy to explore the pre-passivation of sodium metal by fluoroethylene carbonate before potentials are applied

“…23 Following our previous work, electrodeposited Cu 2 Sb anode material was used so SEI species can be observed without interference from binders or additives. 17,[24][25][26][27] For the interested reader, more information on XPS tting and presentation can be found in our previous publications. 17,28 XPS data of all corresponding sodium counter electrodes is present and discussed in the ESI (Table S1, Fig.…”